fptl: fix specular in linear

Assets/ScriptableRenderLoop/fptl/FptlLighting.cs

 				format10 = RenderTextureFormat.ARGB2101010;
 			//@TODO: GetGraphicsCaps().buggyMRTSRGBWriteFlag
 			cmd.GetTemporaryRT(kGBufferAlbedo, -1, -1, 0, FilterMode.Point, RenderTextureFormat.DefaultHDR, RenderTextureReadWrite.Default);
-			cmd.GetTemporaryRT(kGBufferSpecRough, -1, -1, 0, FilterMode.Point, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Default);
+			cmd.GetTemporaryRT(kGBufferSpecRough, -1, -1, 0, FilterMode.Point, RenderTextureFormat.DefaultHDR, RenderTextureReadWrite.Default);
 			cmd.GetTemporaryRT(kGBufferNormal, -1, -1, 0, FilterMode.Point, format10, RenderTextureReadWrite.Linear);
 			cmd.GetTemporaryRT(kGBufferEmission, -1, -1, 0, FilterMode.Point, format10, RenderTextureReadWrite.Linear); //@TODO: HDR
 			cmd.GetTemporaryRT(kGBufferZ, -1, -1, 24, FilterMode.Point, RenderTextureFormat.Depth);